The objective of this research is to develop a digital x-ray mammography system that will significantly improve image quality and usefulness while minimizing x-ray radiation dose to the patient. We propose to build and evaluate a digital slot-scanned system using high resolution detector arrays with x-ray sensitivity near the theoretical limit. The semiconductor detector arrays will have a detective quantum efficiency of about 80% and a Nyquist resolution limit of 21 line pairs per millimeter. Image quality of our system operating In normal contact mode should surpass what can be obtained from conventional film-screen systems in magnification mode even with x-ray radiation exposure reduced by a factor of 5 from that required by conventional systems In contact mode. The inherently digital output of the detector array is ideally suited for Computed RadIology Including: electronic archiving and Image transmission, image enhancement and analysis, and computer aided diagnosis. Specific aims during Phase II are to: * a Build two prototype low dose x-ray digital mammography systems using updated design of the x-ray sensors developed with partial SBIR Phase-I funding. * a Evaluate engineering and clinical performance of these systems with the aim of transferring the prototype technology to commercial production. * a Evaluate advanced x-ray detectors and signal processing circuits to further enhance performance and reduce system cost. PROPOSE COMMERCIAL APPLICATION: The immediate focus of this research project is to develop and evaluate direct imaging, semiconductor x-ray sensors and the associated data acquisition and Image display technologies for integration into commercial mammography equipment. These core technologies, however, can also be readily adapted and commercialized for other clinical imaging applications, such as, 3-D Imaging, computed tomography and imaging in nuclear medicine.